The invention has for an object novel uncharged and cationic naphthalene derivatives and colorants for keratin fibers, for example human hair, containing these compounds.
The dyeing of fibrous materials, particularly of keratin-containing fibers, for example hair, wool or furs, is generally carried out either with oxidation dyes formed by oxidative coupling of one or more developer components with one or more coupler components or with direct dyes. If needed, oxidation-resistant direct dyes can be added to the oxidative system to achieve special color effects. Direct dyes are incorporated into appropriate carrier compositions and then applied to the fibers. This process, generally known as tinting, is simple to use and stands out in that it causes only minor damage to the keratin fibers, because the process does not require the use of ammonia or peroxide. The dyes used, however, must meet a few requirements. They must be toxicologically and dermatologically unobjectionable and must make it possible to obtain colorations of the desired intensity and brilliance. Moreover, they must present high resistance to washing, light, perspiration, permanent waving, acids, bases and rubbing. In any event, such hair colorations must remain stable for at least four to six weeks under currently prevailing everyday conditions.
For a direct, nonoxidative colorant for keratin fibers it is usually necessary to use a combination of different nonoxidative dyes to achieve certain color shades. Because the availability of yellow, red and blue dyes that adequately meet all requirements is limited, a great need still exists for such dyes. Another, very interesting application of direct dyes is their use in agents for simultaneous brightening and dyeing. In these dye compositions which can have a higher oxidant content, further requirements are placed on the dyes used, particularly in terms of sufficient resistance to the oxidants used.